This story originally appeared at Capital & Main.

A proposed 166-well oil and gas project in suburban Denver could imperil a decades-long, multimillion-dollar effort to prevent carcinogenic chemicals stored on one of the nation’s most contaminated industrial sites from leaking into groundwater, letters from federal and state officials show.

Regulators expressed concern in May that drilling underneath and near the Lowry Landfill Superfund Site could cause small cracks in bedrock cradling millions of gallons of toxic waste in 78 unlined trenches. These fissures could allow contaminants to enter an aquifer system that millions of Coloradans rely on, wrote the U.S. Environmental Protection Agency to Civitas, the operator requesting permission to drill. The EPA oversees a complex 40-year effort to protect the health of millions of people living around the site.

The agency’s concerns stem from the issues that have long surrounded hydraulic fracturing, or fracking, a drilling process that has led Colorado in the last decade to become the nation’s fourth largest oil-producing state. The method involves pumping sand and millions of gallons of water and chemicals roughly a mile under the surface to crack shale, and release oil and gas.

“The EPA is concerned that hydraulic fracturing surrounding and underneath the site could lead to a significant unintended release of hazardous substances,” the agency wrote in May to Dan Harrington, who leads Civitas’ development initiatives. This “contamination is held in place by a bedrock layer which could, under certain conditions, be subject to microfractures from fracking.”

In response, Civitas sent a letter to the EPA in September and committed not to drill under the site, saying: “This precaution is not due to any risk associated with oil and natural gas development, but a desire to protect the Superfund remedy that is in place and operating effectively.”

The EPA cited the company’s commitment when asked if it is still apprehensive about Civitas’ plans to drill near the site and said in an email that it will “continue to coordinate with all parties to evaluate these and other site concerns.” Civitas did not return repeated requests for comment.

Natural gas production likely cause of southern Colorado earthquakes, experts say

The operator’s agreement not to drill under the Superfund site failed to reduce the anxiety of scores of households near the 50-square-mile proposed oil and gas project, which includes wells near the Aurora Reservoir. The facility is part of a system of reservoirs that store drinking water for about 390,000 people and is a popular recreation area.

Drilling currently exists about five miles from the Superfund site. Civitas is proposing well pads much closer — within about two miles. But horizontal pipes that extend beneath the proposed production area could come even closer to the site boundary.

The potential for Civitas’ Lowry Ranch oil and gas plan to disturb sensitive Superfund containment efforts brought to the fore long-running uncertainty among technical experts about whether nearby industrial operations, such as fracking, could trigger seismic activity. The U.S. Geological Survey and state agencies mapped faults near the site, as well as near the Aurora Reservoir’s dam.

Questions remain about the presence, and possible growth, of a fault at the northern end of the Superfund site and whether it’s in part responsible for allowing chemicals to leak and create a three-mile-long underground plume. The EPA says this plume doesn’t present a risk to groundwater or surface water.

Scientists have attributed earthquakes in Colorado, Oklahoma and Texas, to a surge in oil and gas operations over the last decade. These temblors were caused by injection wells, which companies drill deep into the earth and use to dispose of millions of gallons of wastewater that flows back up from fracking operations, studies found.

Hydraulic fracturing features a brief application of pressure to rock formations to release oil and gas, while wastewater injection is “an ongoing process that injects significant volumes of wastewater over long periods of time,” said Jill Carlson, an engineering geologist at the Colorado Geological Survey.

“While weak seismic events associated with fracking can be detected by seismometers, I am not aware of any surface shaking, movement or surface/near surface damage caused by fracking,” added Carlson, who is the survey’s deputy director and land-use program manager.

Uncertainty About Oil and Gas Drilling Effects on Public Health 

The Lowry Ranch oil and gas project is proposed on land owned by the Colorado State Land Board on the fringes of Aurora, the state’s third largest city. Much is at stake: Energy companies are planning massive projects ever closer to Denver suburbs, where the industrial activity exposes hundreds of thousands of residents to air pollution, spills, truck traffic and other hazards.

Proposed drilling near a Superfund site also raises new health and safety concerns residents say aren’t adequately addressed in state or local regulations. Increasingly, residents are demanding stricter rules about where fracking can take place and detailed studies that provide benchmarks for how much activity should be allowed.

“The county must insist on studies to understand the potential risks associated with fracking-induced seismicity on both the Lowry Landfill Superfund Site — and the Aurora Reservoir Dam,” wrote Kevin Lynch, an associate professor of law at the University of Denver Environmental Law Clinic, in an October letter to Arapahoe County commissioners on behalf of residents and conservation groups.

Civitas’ refiled its drilling plan on Feb. 23 after making a series of revisions requested by state regulators.  A 60-day public comment period ends April 23, and a hearing on the proposal is scheduled in front of the Energy & Carbon Management Commission for June 26.

The company’s original proposal, filed in 2022, prompted the Arapahoe County Board of County Commissioners to overhaul its  oil and gas rules. The five-member body voted 3 to 2 in November to increase setbacks between wells and reservoirs and occupied structures to 3,000 feet, and to require operators to file water quality plans and to do routine on-site air quality and noise testing.

The county’s new rules are allowed under a 2019 law that requires the state’s oil and gas regulator to prioritize public health and the environment over fostering energy development.

County officials said they plan to study seismicity and other issues this year when staff and commissioners start reviewing a second round of rules aimed at limiting fracking’s impacts on neighborhoods.

This rulemaking will include a proposal to ban wastewater injection wells, “which have been linked to induced seismicity in Colorado,” wrote Anders Nelson, a county spokesperson, in an email.

“We will consider other seismicity concerns as we develop the regulations,” he added, “and seek advice on that topic from the Colorado Geological Survey, EPA and the Colorado Energy and Carbon Management Commission.”

The state land board, which has owned the 26,000 acre Lowry Ranch adjacent to the Lowry Landfill Superfund Site since the 1960s, does not have regulatory or permitting authority over Civitas’ project, wrote Kristin Kemp, the land board’s outreach and communications officer, in an email.

The land board’s assets include 4 million acres of subsurface minerals. Mineral extraction leases accounted for 80% of the $2 billion the agency earned in the last decade and provided as grants to fund capital construction at schools, she said.

“Currently, more than a dozen different operators ranging from agriculture, renewable energy, recreation and mineral extraction hold leases at Lowry Ranch,” Kemp said. A company purchased by Civitas “has held an oil and gas lease on the majority of the Lowry Ranch since 2020.”

On a November conference call, Civitas executives said they are pleased with the firm’s ability to drill farther, faster and with greater production in the Denver Julesburg Basin, the state’s largest oil play along the eastern slope of the Rocky Mountains.

“We’re very excited with how 2024 is shaping up,” said Chief Executive Officer Chris Nolan of the company’s plans to expand drilling operations in the region.

A 40 Year Containment Effort Continues in Perpetuity

As controversy over the safety of new industrial activity near the Lowry Landfill Superfund Site continues, myriad local, state and federal agencies, and companies, responsible for keeping chemicals contained on the site and out of residents’ groundwater and air, never stop working. A five-year review published in 2022 found that the site remedies are “currently protective of human health and the environment.”

The city and county of Denver, which owns the 507-acre site, works with the operator Waste Management to contain pollution. Efforts to reduce and monitor contamination in soils, groundwater and surface water are overseen by the EPA and the Colorado Department of Public Health and Environment.

Containing the more than 138 million gallons of sewage, pesticides, industrial solvents and dozens of other hazardous substances dumped there requires an annual multimillion dollar coordinated effort. It also involves expensive infrastructure, such as a plant that removes methane emitted on the site and 500 regularly monitored water wells installed in the region’s aquifers.

Multiple barriers were built to hold pollution on the site including a slurry wall, a landfill cover, a groundwater extraction trench and a subsurface clay barrier. The EPA isn’t the only agency concerned about how Civitas’ oil and gas drilling proposal might impact the site. The state’s health department and the region’s Democratic congressman, Jason Crow, also expressed concern — both alerted to the issue by homeowners.

“Seismicity is a critical issue,” said Marsha Kamin, a homeowner who was unaware that wells contained in the Lowry Ranch project could be drilled within a mile of her subdivision when she moved in a year ago. “No one is dealing with it.”

On a brisk, gray January afternoon, Kamin joined other residents in a clubhouse with a panoramic view of the ice-choked Aurora Reservoir. They represented the leadership team for Save the Aurora Reservoir, or STAR — created about 18 months ago after Civitas announced its Lowry Ranch drilling proposal. The group recently retained a geologist and an environmental attorney to help them push for stricter rules.

STAR, with more than 1,000 members signed up to receive action alerts on its Facebook page, asked Crow to write a letter to the EPA in October asking what the agency plans to do about the risks posed by oil and gas operations close to the Superfund site.

The agency responded in November that it obtained an agreement from the U.S. Bureau of Land Management not to lease its minerals under the Superfund site, in addition to the acknowledgment from Civitas that it won’t drill below the site. When asked by Capital & Main about the agency’s response, Crow’s office said it will follow the drilling plan as it goes through the state and county approval processes.

“The EPA will need to monitor the Lowry Landfill Superfund Site for decades to come, and thoroughly monitor the impact of this and any proposed projects close to the site,” Crow said in an email response to an interview request. “There should be no question about the safety of Coloradans’ water.”

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